Phase-shifting means

ABSTRACT

A reciprocal latching phase-shifting device which accepts arbitrarily polarized electromagnetic wave energy. A first dual mode transducer converts the incident wave energy into its two orthogonal components and passes each component into a separate waveguide section containing phase-shifter means. The two waveguides are joined at their remote ends by a second dual mode transducer for combining the phase-shifted orthogonal components. The first and second dual mode transducers are identical, and the position of the second transducer is inverted from that of the first. The vertical and horizontal components of the incident wave energy are therefore converted respectively to the horizontal and vertical components of the transmitted wave energy. Each phase shifter means includes a linear polarizer, a 45* rotator, a quarter-wave plate, a ferrite phase shifter, a second quarter-wave plate, a second 45* rotator, and a second linear polarizer orthogonal to the first linear polarizer. The first and second waveguides are formed by plating directly onto the wave energy carrying material of the phase-shifting means. Ferrite shunts between the ferrite phase shifters in the first and second waveguides, at the ends of the ferrite phase shifters, form a closed magnetic circuit between the ferrite phase shifters, thereby allowing operation in a remanent state without the use of a magnetic yoke.

United States Patent [72] Inventors William E. Hord;

James A. Benet, both of St. Louis, Mo. [21] Appl. No. 875,248 22] Filed Nov. 10, 1969 [45] Patented Dec. 7, 1971 [73] Assignee Emerson Electric Co.

St. Louis, Mo.

M [54] PHASE-SHIPPING MEANS 8 Claims, 8 Drawing Figs. [52] U.S. Cl. 333/31 A, 333/21, 333/21 A, 333/24.l [51] lnt.Cl 1101p 1/18 [50] FleldolSearch ..333/1.1,2l, 21 A, 24.1,24.3, 31,31 A, ll [56] References Cited UNITED STATES PATENTS 2,951,215 8/1960 Berk et a1. 333/241 X 3,305,867 2/1967 Miccioliet al.. 3331/24.! UX 3,500,460 3/1970 Jones et a1. 333/24.l X 3,080,536 3/1963 Dewhirst 333/241 Primary xaminer-l-lerman Karl Saalbach Assistant Examiner-Paul L. Gensler Anorney- Polster and Polster ABSTRACT: A reciprocal latching phase-shifting device which accepts arbitrarily polarized electromagnetic wave energy. A first dual mode transducer converts the incident wave energy into its two orthogonal components and passes each component into a separate waveguide section containing phase-shifter means. The two waveguides are joined at their remote ends by a second dual mode transducer for combining the phase-shifted orthogonal components. The first and second dual mode transducers are identical, and the position of the second transducer is inverted from that of the first. The vertical and horizontal components of the incident wave energy are therefore converted respectively to the horizontal and vertical components of the transmitted wave energy. Each phase shifter means includes a linear polarizer, 21 45 rotator, a

' quarter-wave plate, a ferrite phase shifter, a second quarterwave plate, a second 45 rotator, and a second linear polarizer orthogonal to the first linear polarizer. The first and second waveguides are formed by plating directly onto the wave energy carrying material of the phase-shifting means. Ferrite shunts between the ferrite phase shifters in the first and second waveguides, at the ends of the ferrite phase shifters. form a closed magnetic circuit between the ferrite phase shifters, thereby allowing operation in a remanent state without the use ofa magnetic yoke.

PATENTEDHE'C 719m 3.626335 sum 1 0F 3 FIG. 5 maiiws WILUAM E. HOQD JANE-I6 A. BENET mam J1 PATENTED DEC 7 am SHEET 2 OF 3 53 W\LL\AM E. HORD JAMEQB A. BENET {M M! Qz PHASE-SHIPPING MEANS BACKGROUND OF THE INVENTION This invention relates to phase-shifting devices for electromagnetic wave transmission systems, and more particularly to a controllable phase-shifting device. I

Controllable phase-shifting devices vary the phase of a radiofrequency voltage relative to the phase of a reference voltage by an amount which may be controlled by an outside source. One use for such a phase-shifting device is in stationary phased array antenna arrangements, such as those used in electronically scanned radar systems, which include an array of antenna elements each fed through a phase-shifting device. Beam movement is accomplished by selectively varying the relative phase of the RF voltage or electromagnetic wave energy supplied to the antenna.

- Variable phase-shifting devices should ideally have the following characteristics. They should be capable of carrying considerable power. For this purpose, ferrite elements controlled by magnetizing coils have been found to be suitable. They should be reciprocal, that is, they should cause the same effect on wave energy propagated in one direction as in the other direction. Magnetized ferrite does not have this property, but techniques have recently been developed for constructing a reciprocal ferrite phase-shifting device. They should also be latching, that is, they should require power only to change the amount of phase shift they cause. Techniques are now also known for utilizing remanent magnetization to produce a latching ferrite phase-shifting device. They should also be compact and inexpensive. The large number of phase-shifting elements used in a device such as a phased array radar antenna makes these requirements of prime importance. Finally, they should be polarization insensitive, that is, they should be capable of accepting with low-insertion loss electromagnetic wave energy having any arbitrary polarization. I-Ieretofore, no phase shifter has been known which combines all of these desirable characteristics.

One of the objects of this invention is to provide a phaseshifting device which is polarization insensitive, and which may be reciprocal, latching, and capable of carrying high power.

Another object of this invention is to provide such a phaseshifting device which is compact and relatively inexpensive, even as compared with presently known phase-shifting devices incapable of one or more of the functions of the present invention.

Other objects will be obvious to those skilled in the art in the light of the following description and accompanying drawings.

SUMMARY OF THE INVENTION In accordance with one aspect of this invention, a phaseshifting device is provided having a first waveguide section containing first magnetic phase-shifting means, a parallel second waveguide section containing second magnetic means, and means forming a closed magnetic path between the first magnetic means and the second magnetic means for permitting operation of the magnetic means as phase shifters in a remanent state. Means for polarizing a first wave incident on the first magnetic means circularly in a first sense and means for polarizing a second wave incident on the second magnetic means circularly in an opposite sense cause the phase shifi imparted to the first wave to be equal to the phase shift imparted to the second wave.

In accordance with another aspect of the invention, polarization insensitive phase-shifting means are provided comprising waveguide means including first and second waveguide sections, first transducer means comprising means forconverting applied polarized electromagnetic wave energy into its orthogonal linear polarization components, first phase shifter means in the first waveguide section for shifting the phase of the first orthogonal components, second phase shifter means in the second waveguide section for shifting the phase of the second orthogonal component, and second transducer means including means for combining the phase-shifted first orthogonal linear polarization components and the phaseshifted second orthogonal linear polarization component. The first transducer has a first arm in the first waveguide section for passing the first of the orthogonal components and a second arm in the second waveguide section for passing the second orthogonal component, and the second means includes a first arm in the second waveguide section for passing the phase-shifted second orthogonal component and 'a second arm in the first waveguide section for passing the phase-shifted first orthogonal component. The first phase shifter means in disposed between the first arm of the first means and the second arm of the second means, and the second phase shifter means is disposed between the second arm of the first means and the first arm of the second means. In the preferred embodiment the lengths of the first arms of the transducers are identical with each other and the lengths of the second arms of the transducers are identical, and the length of the first arms is different from the length of the second arms. Also in the preferred embodiment, the transducers are identical, and the polarizations of the phase-shifted first and second components at the second transducer means are respectively the same as the polarizations of the second and first orthogonal components at the first transducer means. Also in the preferred embodiment, the first and second waveguide sections are square in cross section and are plated directly onto a wavecarrying solid made of ceramic and ferrite sections.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a view in perspective of one illustrative embodiment of phase-shifting device of this invention;

FIG. 2 is a longitudinal cross-sectional view of the device shown in FIG. 1; taken along the line 2-2 of FIG. 1;

FIG. 3 is a sectional view taken along the line 33 of FIG.

FIG. 4 is a sectional view taken along the line 4-4 of FIG. 2;

FIG. 5 is a view in perspective of a dual mode transducer portion of the device shown in FIGS. 1 and 2;

FIG. 6 is a longitudinal cross-sectional view of the transducer portion of FIG. 5;

FIG. 7 is a view in right end elevation as viewed in FIGS. 5 and 6 of the transducer portion of FIGS. 5 and 6; and

FIG. 8 is a diagrammatic view, showing the changes in polarization of wave energy passing through the device shown in FIGS. 1-4.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawings, reference numeral 1 indicates one illustrative embodiment of phase-shifting device of this invention. The phase-shifting device 1 includes elongated waveguide means 20 having at its left end portion, as viewed in FIGS. 1 and 2, a first dual mode transducer 30 and having at its right-hand portion a second dual mode transducer 40. Between the first transducer 30 and the second transducer 40 the waveguide 20 is bifurcated to form a first waveguide section 21 and a second waveguide section 22. Each waveguide section 21 and 22 includes, from left to right, a 45 rotator 50 and 50', a circular polarizer 60 and 60' respectively, a variable magnetic field phase shifter 70 and 70 respectively, a second circular polarizer and 80' respectively, and a second 45 Faraday rotator and 90 respectively. Each of the sections 21 and 22 also includes an arm of each transducer 30 and 40.

The design of the dual mode transducers is shown in detail in FIGS. 5-7, and this design forms part of the subject matter of James A. Benet US. application Ser. No. 875,247, filed Nov. 10, I969, now abandoned.

The dual mode transducers 30 and 40 are identical. The first transducer 30 is made of a ceramic material and includes an input arm 31, a first output arm '32 and a second output arm 33. It will be understood that the terms input" output are used only for convenience in describing the configuration of the dual mode transducers 30 and 40, and that the transducer 30 is capable of accepting orthogonal waves through its output arms and emitting a composite elliptically polarized wave through the input" arm. The arms 3133 are generally square in cross section and are dimensioned to transmit electromagnetic wave energy of the desired wavelength (that is, in the desired wave band) in both the TE and TE modes. The free end of the input arm 31 fonns an input aperture 31a, and the free ends of the output arms 32 and 33 form output apertures 32a and 330 respectively. The input arm 31 and output arm 32 are linearly aligned and form a single straight waveguide section. A second output arm 33 includes a section 33b which meets the output arm 32 to form a junction 34. The section 33b of the second output arm 33 is perpendicular to the first output arm 32. A bend section 33c joins the section 33b with a section 33d of the second output arm 33 parallel to the first output arm 32. The output apertures 32a and 33a lie in the same plane perpendicular to the long axes of the output arm 32 and the parallel section 33d of the second output arm 33. The output arm 32a is split in half along a plane perpendicular to the axes of the output arm to the section 33b of the second output arm 33. A thin reflective shim 35 is positioned across the split, and to the right of the shim 35 a thin resistive film 36 is positioned in the split. The reflective shim 35 and resistive film 36 may be made of known suitable materials and the portion of the arm removed in the process of forming the split may be replaced using a suitable adhesive. The first reflective shim 35 extends approximately one-third of the way into the junction 34. The second output arm 33 is also split in half at a distance of about one-half wavelength of the frequency to be carried by the transducer from the junction 34. The split is perpendicular to the split in the first output am 32 and contains the longitudinal axis of the parallel section 33d of the second output arm 33. The portion of the split in the perpendicular section 33b and bend section 33c of the arm 33 is provided with a reflective metal foil shim 37, and the parallel section 33d is provided with a thin resistive film 38. The reflective shim 37 and resistive film 38 are secured in the split, and the portion of the arm 33 removed in forming the split is replaced using a suitable adhesive.

The second dual mode transducer 40 is identical with the first dual mode transducer 30 and includes an output arm 41 identical with the input 31 of the first transducer, a first input arm 42 and a second input arm 43 identical with the first and second output arms 32 and 33 respectively of the first transducer 30. The arms 42 and 43 include reflective shims 45 and 47 and resistive films 46 and 48 respectively, identical with the reflective shims 35 and 37 and resistive films 36 and 38 respectively of the first transducer 30.

The first output arm 32 of the first transducer 31 and the second input arm 43 of the second transducer 40 form the end portions of the first waveguide section 21, and the second output arm 33 of the first transducer 31 and the first input arm 42 of the second transducer 40 form the end portions of the second waveguide section 22. Between the transducers, the waveguide sections 21 and 22 are mirror images with respect to a plane between them. The Faraday rotators 50 and 50 have the same cross section as the output aperture 32a and 330 respectively of the first transducer 30. Each rotator 50 and 50' includes a piece 51 and 51 of magnetic material, such as a suitable ferrite material, within the waveguide 20, and a permanent magnet 52 secured to the opposed faces of the waveguide sections 21 and 22 adjacent the magnetic pieces 51 and 51'. The magnet 52 predeterminately magnetizes both of the ferrite elements 51 and 51' so as to provide a substantially 45 rotation to the plane of a linearly polarized wave of the desired wavelength propagating therethrough. Both ferrite elements are magnetized in the same longitudinal direction.

The circular polarizers 60 and 60 each include a dielectric piece 61 and 61 such as a ceramic piece of suitable dielectric constant. Opposed faces of the ceramic pieces 61 and 61 are provided with flats 62 and 62'. The circular polarizer 60 and 60' act as quarter-wave plates, so that a linearly polarized wave entering the polarizers 60 and 60 in a plane diagonal of the square waveguide section 21 and 22 is converted to a circularly polarized wave, and a circularly polarized wave entering the polarizer 60 and 60' is converted into a linearly polarized wave.

The controllable phase shifters and 70 include elongated pieces 71 and 71' of square cross section, formed of a magnetic material such as a suitable ferrite material. The ferrite pieces 71 and 71 are contained in the waveguide sections 21 and 22 respectively. At the ends of the magnetic pieces 71 and 71', between the opposing outer faces of the waveguide sections 21 and 22 are a pair of blocks 72 and 73. The blocks 72 and 73 form a closed magnetic circuit between the magnetic pieces 71 and 71'. The magnetic blocks 72 and 73 may be made of the same magnetic material as the magnetic pieces 71 and 71'. Control coils 74 and 74' surround the waveguide sections 21 and 22 in the region of the magnetic pieces 71 and 71. The coils 74 and 74' may be connected to a source of voltage pulses through leads 75 and 75' for controlling the magnetization of the magnetic pieces 71 and 71'. The magnetic blocks 72 and 73 form pole pieces when the coils 74 and 74 are energized, and provide a substantially closed flux path so that the remanent field in the magnetic pieces 71 and 71' is retained at a desired level after each application of control current pulses.

The second circular polarizers and 80' include ceramic pieces 81 and 81' in the waveguide sections 21 and 22. The pieces 81 and 81 have flats 82 and 82 on their lateral outer faces. The flats 82 and 82 are therefore perpendicular with respect to the flats 62 and 62' of the first circular polarizers 60 and 61. The second 45 Faraday rotators and 90 are identical with the first rotators 50 and 50', and include thin pieces of magnetic material 91 and 91 in the waveguide sections 21 and 22 and a permanent magnet 92 between the opposing outer faces of the waveguide section 21 and 22. The permanent magnet 92 provides the same predeterminate magnetization in the same longitudinal direction as the magnet 52 of the first rotator 50 and 50'.

The various ceramic and magnetic pieces are cemented with a suitable adhesive, and the device is plated with a suitable metal to form the completed waveguide 20. The magnets 52 and 92 and the blocks 72 and 73 are then secured in place and the coils 74 and 74 are wound around the first and second waveguide sections 21 and 22. If desired, some or all of the final shaping of the exterior faces of the device may be performed after the ceramic and magnetic pieces are adhered to one another but before the device is plated.

The ceramic and ferrite pieces are chosen so that they have similar dielectric constants. The magnetic pieces may, for example, be formed of a ferrite material containing magnesiummanganese or other well-known materials such as garnet material, for example, yttrium-iron garnet.

The operation of the phase-shifting device 1 is as follows. ln the following discussion, it will be assumed that there is a predetermined remanent magnetic field in the phase shifter magnetic pieces 71 and 71.

An arbitrarily polarized wave, such as indicated by electric field vector 100, entering the input aperture 31a of the waveguide 20 is converted into its orthogonal components by the square input section 31, that is it propagates in the TE and TE modes. The reflective shim 37 in the second arm 33 acts as a strong impedance to the vertically polarized component 101 of the incident wave, and consequently this component continues through the first output arm 32. The vertically polarized component is substantially unaffected by the reflective shim 35 or by the resistive film 36 which absorbs any stray cross-polarized energy. As the vertically polarized vertical component 101 propagates through the predeterminately axially magnetized ferrite element 51 of the Faraday rotator 50, the plane of polarization of the wave is rotated 45 as shown by vector 102. As the wave energy passes through the circular polarizer 60 it is converted into a circularly polarized wave having a first sense of circular polarization, as indicated by the arrow 103.

It has been determined that the nonnal mode of transmission in a square, axially magnetized ferrite-filled waveguide is circular polarization. Therefore, as the circularly polarized wave energy propagates through the ferrite piece 71, it will be subjected to a relative phase shift 1 The phase-shifted circularly polarized field is indicated by the arrow 104.

As the phase-shifted vertical component propagates through the second circular polarizer 80, it is converted from a circularly polarized wave to a linearly polarized wave, ad indicated by the vector 105. The polarization of the vertical component at the output end of the circular polarizer 80 is rotated 225 relative to the vertical component in the first dual mode transducer 30. The second rotator 90 rotates the plane of the vertical component an additional 45 in the same direction as the first rotator 50. The plane of polarization of the vertical component is thus rotated through 270 as it propagates through the waveguide, so that it is horizontally polarized as it enters the second transducer 40, as indicated by the vector 106. The resistive film 48 of the second arm 43 of the second transducer 40 absorbs any cross-polarized RF energy, but allows the horizontally polarized vertical component to pass substantially unaffected. This component is then emitted from the output aperture 41a of the second transducer 40.

The horizontally polarized component 111 of the incident wave 100 is blocked by the reflective shim 35 from entering the first output arm 32. The shim 35 is positioned to create a coupling effect with the second output arm 33 and directs the horizontal component 111 of the incident wave 100 into the second output arm 33. The horizontally polarized component is substantially unaffected by the reflective shim 37 or by the resistive film 38 which absorbs any stray cross-polarized energy. As the horizontally polarized horizontal component propagates through the predeterminately axially magnetized ferrite element 51' of the Faraday rotator 50, the plane of polarization of the wave is rotated 45, in the same direction as the plane of the vertical component, as shown by vector 112. As the wave energy passes through the circular polarizer 60 it is converted into a circularly polarized wave having a second sense of circular polarization, opposite that of the vertical component, as indicated by the arrow 113.

Because the direction of circular polarization of the horizontal component is opposite that of the vertical component, and the direction of magnetization of the ferrite piece 71 is opposite that of the first ferrite piece 71, the circularly polarized wave energy of the horizontal component will be subjected to a relative phase shift 1 identical with the phase shift I the circularly polarized wave energy of the first component. The phase-shifted circularly polarized field is indicated by the arrow 114.

As the phase-shifted horizontal component propagates through the second circular polarizer 80', it is converted from a circularly polarized wave to a'linearly polarized wave, as indicated by the vector 115. The polarization of the horizontal component at the output end of the circular polarizer 80' is also rotated 225 relative to the horizontal component in the first dual mode transducer 30. The second rotator 90' rotates the plane of the horizontal component an additional 45 in the same direction as the first rotator 50'. The plane of polarization of the horizontal component is thus rotated through 270 as it propagates through the waveguide, so that it is vertically polarized as it enters the second transducer 40, as indicated by the vector 116. The resistive film 46 of the first arm 42 of the second transducer 40 absorbs any cross-polarized RF energy, but allows the vertically polarized horizontal component to pass substantially unaffected. This component is then emitted from the output aperture 410 of the second transducer 40, in

phase with the horizontally polarized vertical component. It will be seen that the output wave energy is a linearly polarized composite wave having a vertical component equal in amplitude to the horizontal component of the incident wave and a horizontal component equal to the vertical component of the incident wave. The output wave is indicated by the vector 117. The plane of polarization of the emitted wave is thus rotated 90 from that of the incident wave.

Considering now wave energy propagating through the phase-shifting device 1 in the opposite direction, i.e., from the right end of the left end of the waveguide 20, the wave, indicated by electric field vector 120, enters the output aperture 41a of the second transducer 40 and is converted into its orthogonal components. The horizontally polarized component 121 of the incident wave 120 is reflected by the shim 45 into the second input arm 43. This component is substantially unaffected by the reflective shim 47 or resistive film 48. The Faraday rotator 90 rotates the plane of the horizontal component 45 as indicated by the vector 122. The circular polarizer converts the linearly polarized wave to a circularly polarized wave, as indicated by arrow 123. The sense of this circularly polarized wave, of course, is opposite the sense of circular polarization that the previously described wave energy had as it traveled through this same waveguide section 21 in the opposite direction. As the wave propagates through the ferrite piece 71, it is subjected to the same relative phase shift 1 was the wave energy traveling through this element 71 in the opposite direction. The phase shifted circularly polarized field is indicated by the arrow 124.

As the phase-shifted horizontal component propagates through the first circular polarizer 60, it is converted from a circularly polarized wave to a linearly polarized wave, as indicated by the vector 125. The first rotator 50 rotates the plane of the horizontal component an additional 45 in the same direction as the second rotator 90, so that the plane of polarization of the horizontal component traveling from right to left is rotated through 270 from horizontal to vertical polarization, as indicated by the vector 126. The vertically polarized wave energy passes through the resistive film 36 and the shim 35 substantially unaffected and is emitted from the input aperture 310 of the first transducer 30.

The vertical component 131 of the incident wave 120 is passed by the shim 45 in the first arm 42 of the second transducer 40. The second rotator rotates the plane of the vertical component 45", in the same direction as the plane of the horizontal component, as shown by vector 132. As the wave energy passes through the second circular polarizer 80', it is converted into a circularly polarized wave having a sense of circular polarization opposite that of the horizontal component 121, as indicated by the arrow 133.

The circularly polarized wave energy of the horizontal component will be subjected to a relative phase shift l identical with the phase shift I of the circularly polarized wave energy of the horizontal component in traveling from right to left. The phase-shifted circularly polarized field is indicated by the arrow 134.

As the phase-shifted vertical component propagates through the first circular polarizer 60', it is converted from a circularly polarized wave to a linearly polarized wave, as indicated by the vector 135. The first rotator 50' rotates the plane of the vertical component an additional 45 in the same direction as the second rotator 90, so that the plane of polarization of the vertical component is rotated through 270 as it propagates through the waveguide from right to left, and the horizontal component is vertically polarized as it enters the first transducer, as indicated by the vector 136. The resistive film 38 and reflective shim 37 of the second arm 33 of the first transducer 30 allow the horizontally polarized vertical component to pass substantially unaffected. This component is then emitted from the input aperture 31a of the first transducer 30, in phase with the vertically polarized horizontal component. Again, the output wave energy is a linearly polarized composite wave having a plane of polarization rotated 90 from that of the incident wave, as indicated by the vector 137.

It will be seen that if a wave is transmitted from left to right through the phase-shifting device of this invention and a wave having the same polarization as the emitted wave, such as a return wave reflected by a target in a radar application, is transmitted back through the device from right to left, the return" wave will have the same polarization at the input aperture 31a at the left-hand end of the device as did the original wave. Furthermore, the relative phase shift to which it .is subjected in passing through the device will be same in either direction. The amount of this phase shift may be varied by changing the remanent magnetization of the ferrite pieces 71 and 71. Control of the remanent magnetization of the pieces 71 and 71 can be accomplished, for example, by first applying a square wave pulse to one coil, such as coil 74, to produce saturation of the closed magnetic circuit composed of the ferrite pieces 71 and 71' and the magnetic shunts 72 and 73. A square wave pulse is then supplied to the other coil 74' to preset the flux level of the magnetic circuit to a point just beyond the knee of the magnetization curve of the elements, and then supplying a second square wave pulse to the coil 74 which provides the desired latching, i.e., level of remanent magnetization. In this way, the linear portion of the magnetization curve can be used so that the phase shift will be approximately proportional to pulse width. Thus, the amount of phase shift of wave energy propagating through the device )1 may be readily controlled, for example, by varying the width of the control pulse.

Since the remanent flux level of the ferrite pieces 71 and 7 ll is controlled by the control pulses, the necessity of continuous control power is avoided, and it is not necessary to apply control pulses to the coils 74 and 74 unless it is desired to Change the amount of phase shift.

Impedance matching elements can be typically incorporated at the end of the waveguide section so as to couple the device properly in the transmission system used.

Because the waveguide 20 is filled by dielectric and ferromagnetic materials, and because the device needs only the coils 74 and 74 outside the periphery of the waveguide 20, it is extremely compact and may be used in applications requiring a high density of such devices, as for example in a phased array antenna application.

Numerous variations in the arrangement and construction of the phase-shifting device of this invention, within the scope of the appended claims, will occur to those skilled in the art in the light of the foregoing description.

Having thus described the invention, what is claimed and desired to be secured by Letters Patent is:

l. Phase-shifting means, for use in an electromagnetic wave transmission system, for accepting incident wave energy having an arbitrary polarization and emitting substantially all of said wave energy, said phase-shifting means selectively shifting the phase of said emitted wave energy, the polarization of said emitted wave energy being dependent on the polarization of said incident wave energy, said phaseshifting means comprising waveguide means; first and second waveguide sections in said waveguide means, first transducer means in said waveguide means, said first transducer means comprising means for accepting applied arbitrarily polarized electromagnetic wave energy and for converting said wave energy into its orthogonal polarization components, said first transducer means having a first arm in said first waveguide section for passing the first of said orthogonal components and a second arm in said second waveguide section for passing the second of said orthogonal components; first phase shifter means in said first waveguide section for shifting the phase of said first component; second phase shifter means in said second waveguide section for shifting the phase of said second component; and second transducer means in said waveguide means, said second transducer means comprising means for combining the phase-shifted first component and the phaseshifted second component and for emitting wave energy having a polarization made up of the combined polarizations of the phase-shifted first and second components, said second transducer means having a first arm in said second waveguide section for passing said phase-shifted second component and a second arm in said first waveguide section for passing said phase-shifted first component, said first phase shifter means being disposed between said first arm of said first transducer means and said second arm of said second transducer means, and said second phase shifter means being disposed between said second arm of said first transducer means and said first arm of said second transducer means, said first waveguide section and said second waveguide section being isolated from each other with respect to wave energy passing therethrough.

2. The phase-shifting means of claim 1 wherein said first arm of said first transducer means and said first arm of said second transducer means have the same effective length, and said second arm of said first transducer means and said second arm of said second transducer means have the same effective length, the efiective length of said first arms being difierent from the effective length of said second arms.

3. The phase-shifting means of claim 1 wherein each of said first and second waveguide sections is substantially square in cross section substantially throughout its length.

41. The phase-shifting means of claim 1 wherein said phaseshifting means is composed essentially of solid sections of ferrite and ceramic cemented together and coated directly with a metal.

5. The phase-shifting means of claim 1 wherein said first transducer converts said incident wave energy into its orthogonal linear polarization components and wherein said first phase shifter means comprise, in series, first means for converting applied linearly polarized electromagnetic wave energy into substantially circularly polarized wave energy, a first longitudinally magnetizable, controllable ferrite phase shifter, and second means for converting said phase shifted circularly polarized wave energy to linearly polarized wave energy, and wherein said second phase shifter means com prise, in series, third means for converting applied linearly polarized electromagnetic wave energy into substantially circularly polarized wave energy, a second longitudinally magnetizable, controllable ferrite phase shifter, and fourth means for converting said phase-shifted circularly polarized wave energy to linearly polarized wave energy.

6. The phase-shifting means of claim 5 including means forming a closed magnetic path between said first ferrite phase shifter and said second ferrite phase shifter for permitting operation of said first and second ferrite phase shifters in a remanent state; said first means and said third means polarizing said wave energy in opposite circular senses, said ferrite phase shifters being of equal length, whereby the phase shift imparted to the first wave in passing through said first phase shifter is identical with the phase shift imparted to the second wave in passing through said second phase shifter, and said second means and said fourth means converting said phase shifted circularly polarized wave energy to linearly polarized wave energy, polarized orthogonally to the wave energy received by the first means and the third means respectively.

7. The phase-shifting means of claim 6 wherein each of said first, second, third and fourth means comprises a linear polarizer, a 45 Faraday rotator and a quarter-wave plate arranged in series between one of said transducer arms and one of said phase shifter means.

8. Phase-shifting means, for use in an electromagnetic wave transmission system, for accepting incident wave energy having any arbitrary polarization and emitting substantially all of said wave energy, said phase-shifting means selectively shifting the phase of said emitted wave energy, comprising waveguide means; first and second waveguide sections in said waveguide means, first transducer means in said waveguide means, said first transducer means comprising means for accepting applied arbitrarily polarized electromagnetic wave energy and for converting said wave energy into its orthogonal linear polarization components, said first transducer means having a first arm in said first waveguide section for passing the first of said orthogonal linear polarization components and a second arm in said second waveguide section for passing the second of said orthogonal linear polarization components;

said second waveguide section for passing said phase-shifted second component and a second arm in said first waveguide section for passing said phase-shifted first component, said first phase shifter means being disposed between said first arm of said first transducer means and said second arm of said second transducer means, and said second phase shifter means being disposed between said second arm of said first transducer means and said first arm of said second transducer means. 

1. Phase-shifting means, for use in an electromagnetic wave transmission system, for accepting incident wave energy having an arbitrary polarization and emitting substantially all of said wave energy, said phase-shifting means selectively shifting the phase of said emitted wave energy, the polarization of said emitted wave energy being dependent on the polarization of said incident wave energy, said phase-shifting means comprising waveguide means; first and second waveguide sections in said waveguide means, first transducer means in said waveguide means, said first transducer means comprising means for accepting applied arbitrarily polarized electromagnetic wave energy and for converting said wave energy into its orthogonal polarization components, said first transducer means having a first arm in said first waveguide section for passing the first of said orthogonal components and a second arm in said second waveguide section for passing the second of said orthogonal components; first phase shifter means in said first waveguide section for shifting the phase of said first component; second phase shifter means in said second waveguide section for shifting the phase of said second component; and second transducer means in said waveguide means, said second transducer means comprising means for combining the phase-shifted first component and the phaseshifted second component and for emittinG wave energy having a polarization made up of the combined polarizations of the phaseshifted first and second components, said second transducer means having a first arm in said second waveguide section for passing said phase-shifted second component and a second arm in said first waveguide section for passing said phase-shifted first component, said first phase shifter means being disposed between said first arm of said first transducer means and said second arm of said second transducer means, and said second phase shifter means being disposed between said second arm of said first transducer means and said first arm of said second transducer means, said first waveguide section and said second waveguide section being isolated from each other with respect to wave energy passing therethrough.
 2. The phase-shifting means of claim 1 wherein said first arm of said first transducer means and said first arm of said second transducer means have the same effective length, and said second arm of said first transducer means and said second arm of said second transducer means have the same effective length, the effective length of said first arms being different from the effective length of said second arms.
 3. The phase-shifting means of claim 1 wherein each of said first and second waveguide sections is substantially square in cross section substantially throughout its length.
 4. The phase-shifting means of claim 1 wherein said phase-shifting means is composed essentially of solid sections of ferrite and ceramic cemented together and coated directly with a metal.
 5. The phase-shifting means of claim 1 wherein said first transducer converts said incident wave energy into its orthogonal linear polarization components and wherein said first phase shifter means comprise, in series, first means for converting applied linearly polarized electromagnetic wave energy into substantially circularly polarized wave energy, a first longitudinally magnetizable, controllable ferrite phase shifter, and second means for converting said phase shifted circularly polarized wave energy to linearly polarized wave energy, and wherein said second phase shifter means comprise, in series, third means for converting applied linearly polarized electromagnetic wave energy into substantially circularly polarized wave energy, a second longitudinally magnetizable, controllable ferrite phase shifter, and fourth means for converting said phase-shifted circularly polarized wave energy to linearly polarized wave energy.
 6. The phase-shifting means of claim 5 including means forming a closed magnetic path between said first ferrite phase shifter and said second ferrite phase shifter for permitting operation of said first and second ferrite phase shifters in a remanent state; said first means and said third means polarizing said wave energy in opposite circular senses, said ferrite phase shifters being of equal length, whereby the phase shift imparted to the first wave in passing through said first phase shifter is identical with the phase shift imparted to the second wave in passing through said second phase shifter, and said second means and said fourth means converting said phase shifted circularly polarized wave energy to linearly polarized wave energy, polarized orthogonally to the wave energy received by the first means and the third means respectively.
 7. The phase-shifting means of claim 6 wherein each of said first, second, third and fourth means comprises a linear polarizer, a 45* Faraday rotator and a quarter-wave plate arranged in series between one of said transducer arms and one of said phase shifter means.
 8. Phase-shifting means, for use in an electromagnetic wave transmission system, for accepting incident wave energy having any arbitrary polarization and emitting substantially all of said wave energy, said phase-shifting means selectively shifting the phase of said emitted wave energy, comprising waveguide means; first and second waveguide sections in saiD waveguide means, first transducer means in said waveguide means, said first transducer means comprising means for accepting applied arbitrarily polarized electromagnetic wave energy and for converting said wave energy into its orthogonal linear polarization components, said first transducer means having a first arm in said first waveguide section for passing the first of said orthogonal linear polarization components and a second arm in said second waveguide section for passing the second of said orthogonal linear polarization components; first phase shifter means in said first waveguide section for shifting the phase of said first component; second phase shifter means in said second waveguide section for shifting the phase of said second component; and second transducer means in said waveguide means, said second transducer means comprising means for combining the phase-shifted first component and the phase-shifted second component and for emitting wave energy having a polarization made up of the combined polarizations of the phase-shifted first and second components, said second transducer means having a first arm in said second waveguide section for passing said phase-shifted second component and a second arm in said first waveguide section for passing said phase-shifted first component, said first phase shifter means being disposed between said first arm of said first transducer means and said second arm of said second transducer means, and said second phase shifter means being disposed between said second arm of said first transducer means and said first arm of said second transducer means. 